The hepatitis B virus belongs to the family of hepadnaviridae. It can cause acute and/or persistent or progressive chronic diseases. Many other clinical manifestations in the pathological morphology can be also caused by HBV—in particular chronic hepatitis, cirrhosis and hepatocellular carcinoma. Additionally, coinfection with hepatitis D virus may have adverse effects on the progress of the disease.
The conventional medicaments approved to be used for treating chronic hepatitis are interferon and lamivudine. However, the interferon has just moderate activity but has an adverse side reaction. Although lamivudine has good activity, its resistance develops rapidly during the treatment and relapse effects often appear after the treatment has stopped. The IC50 value of lamivudine (3-TC) is 300 nM (Science, 2003, 299, 893-896).
PCT Publication No. WO2008154817 discloses a series of compounds used for preventing, managing, treating or lessening a viral disease in a patient, particularly HBV infection or a disease caused by HBV infection. The patent also provides the processes for preparation of specific compounds, such as ethyl 4-(2-bromo-4-fluorophenyl)-6-(morpholinomethyl)-2-(thiazol-2-yl)-1,4-dihydropyrimidine-5-carboxylate as shown in Formula (Ib).

PCT Publication No. WO2008009210 discloses a series of optically pure compounds and preparation method thereof, which used for preventing, managing, treating or lessening an acute or chronic viral disease in a patient, particularly an acute or chronic HBV disease. The patent also provides the processes for preparation of specific compounds, such as, (R)-ethyl 4-(2-chloro-4-fluorophenyl)-6-methyl-2-(thiazol-2-yl)-1,4-dihydropyrimidine-5-carboxylate.
Dihydropyrimidine derivatives can be prepared by several methods described in prior arts, such as patents WO1999054329, WO2008154817, WO2001068641 and WO2010069147, and so on. But the process for preparing an optically pure dihydropyrimidine compound disclosed herein has not yet been published.